Fix beta CI (#1311)

web/_tool/verify_packages.dart

@@ -11,8 +11,6 @@ import 'common.dart';
 void main() async {
   final packageDirs = listPackageDirs(Directory.current)
       .map((path) => p.relative(path, from: Directory.current.path))
-      // TODO: remove this when `slide_puzzle` is removed from samples repo
-      .where((path) => !path.contains('slide_puzzle'))
       .toList();
 
   print('Package dirs:\n${packageDirs.map((path) => '  $path').join('\n')}');